1,881 research outputs found
Outage Probability of Multiple-Input Single-Output (MISO) Systems with Delayed Feedback
We investigate the effect of feedback delay on the outage probability of
multiple-input single-output (MISO) fading channels. Channel state information
at the transmitter (CSIT) is a delayed version of the channel state information
available at the receiver (CSIR). We consider two cases of CSIR: (a) perfect
CSIR and (b) CSI estimated at the receiver using training symbols. With perfect
CSIR, under a short-term power constraint, we determine: (a) the outage
probability for beamforming with imperfect CSIT (BF-IC) analytically, and (b)
the optimal spatial power allocation (OSPA) scheme that minimizes outage
numerically. Results show that, for delayed CSIT, BF-IC is close to optimal for
low SNR and uniform spatial power allocation (USPA) is close to optimal at high
SNR. Similarly, under a long-term power constraint, we show that BF-IC is close
to optimal for low SNR and USPA is close to optimal at high SNR. With imperfect
CSIR, we obtain an upper bound on the outage probability with USPA and BF-IC.
Results show that the loss in performance due to imperfection in CSIR is not
significant, if the training power is chosen appropriately.Comment: Submitted to IEEE Transactions on Communications Jan 2007, Revised
Jun 2007, Revised Nov 200
Sum of Products of Read-Once Formulas
We study limitations of polynomials computed by depth two circuits built over read-once formulas (ROFs). In particular,
1. We prove an exponential lower bound for the sum of ROFs computing the 2n-variate polynomial in VP defined by Raz and Yehudayoff [CC,2009].
2. We obtain an exponential lower bound on the size of arithmetic circuits computing sum of products of restricted ROFs of unbounded depth computing the permanent of an n by n matrix. The restriction is on the number of variables with + gates as a parent in a proper sub formula of the ROF to be bounded by sqrt(n). Additionally, we restrict the product fan in to be bounded by a sub linear function. This proves an exponential lower bound for a subclass of possibly non-multilinear formulas of unbounded depth computing the permanent polynomial.
3. We also show an exponential lower bound for the above model against a polynomial in VP.
4. Finally we observe that the techniques developed yield an exponential lower bound on the size of sums of products of syntactically multilinear arithmetic circuits computing a product of variable disjoint linear forms where the bottom sum gate and product gates at the second level have fan in bounded by a sub linear function.
Our proof techniques are built on the measure developed by Kumar et al.[ICALP 2013] and are based on a non-trivial analysis of ROFs under random partitions. Further, our results exhibit strengths and provide more insight into the lower bound techniques introduced by Raz [STOC 2004]
Process optimization of supercritical carbon dioxide (SC-CO2) extraction parameters for extraction of deoxynojirimycin (1-DNJ) from mulberry (Morus alba L.) leaves
In the present study, supercritical fluid extraction (SFE) technology was applied to extract deoxynojirimycin (1-DNJ) from mulberry leaf powder using carbon dioxide (CO2) as major extraction solvent with ethanol as cosolvent, and extraction parameters such as pressure (100, 150 and 200 bar), temperature (40, 50 and 60 °C) anddynamic extraction time (40, 60 and 80 min) were systematically investigated by full factorial design to obtain the optimum extraction efficiency and extraction yield. Under optimized conditions (pressure of 200 bar, temperature of 50 °C and dynamic extraction time of 80 min), DNJ enriched extract was obtained with high extraction efficiency (96.46 %) and extraction yield (13.41 %), enabling this product to use for nutraceutical purpose. The results indicated that SC-CO2 extraction is a promising and alternative process for recovering the bioactive compounds from mulberry leaves
Physiological characterization of Jasmine flower (Jasminum sambac) senescence during storage
The aim of this work was to identify metabolic differences and hormonal profiles in jasmine flower (Jasminum sambac) and to investigate the possibility that experimental promotion of retardation of the senescence of jasmine flower may mediated by abscisic acid (ABA) and phenolic content. Determinations of ABA and phenols were made in flower senescing under different conditions using two different packaging materials such as polyethylene (PE) and polypropylene (PP) of 200 gauge micron thickness with no ventilation. Pre-treatment of 4 % boric acid for jasmine flowers was selected. Abscisic acid levels in petals also increased during senescence 91.27 pmol g-1, but much less in boric acid-treated jasmine flower 34.16 pmol g-1. However, the lowest content of total phenolics was measured in buds and partially opened flowers 50.90 μg/g but highest in fully opened 61.80 μg/g on the fourth day of storage, respectively. It was concluded that boric acid prevented the early rise in ethylene production and considerably improved jasmine flower shelf-life
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Hydroxyurea-induced hyperpigmentation with iron deposition
Hydroxyurea is a chemotherapeutic agent that is used in the treatment of various hematological diseases including chronic myelogenous leukemia, polycythemia vera, and sickle cell anemia. Hydroxyurea is also used to treat psoriasis. Drug-induced hyperpigmentation is a known cutaneous side effect of hydroxyurea along with xerosis, dermal ulcers, and dermatomyositis-like eruptions. Hyperpigmentation has been observed in the oral mucosa, nails, and in a generalized or a diffuse pattern. The mechanism of hyperpigmentation related to hydroxyurea is believed to be correlated with increased melanin. Classically, clinical types of diffuse hyperpigmentation owing to iron deposition in the dermis have been associated with minocycline and not with hydroxyurea. We report a novel case in which hydroxyurea hyperpigmentation is associated with iron deposition
Automatic Attendance Monitoring System
The attendance is taken in every organization.
Traditional approach for attendance is, professor calls student
name & record attendance. For each lecture this is wastage of
time. To avoid these losses, we are about to use automatic
process which is based on image processing. In this project
approach, we are using face detection & face recognition
system. The first phase is pre-processing where the face
detection is processed through the step image processing. It
includes the face detection and face recognition process.
Second phase is feature extraction. Step by step execution of
these techniques (Image Processing) helps to achieve the final
output. The working of this project is to detect and recognize
the face and mark the attendance for the corresponding face
in the database. Input of this project is face detection and
recognition and output is to mark the attendance. Our project
is being presented as a solution for the Automatic Attendance
Marking System. It is designed to be reliable and low power.
The Automatic face detection and recognition proposed to
attendance marking in database acts as the solution for the
automatic attendance marking system.
Wound Healing Ethnomedicinal Plants Popular among the Malayali Tribes in Vattal Hills, Dharmapuri, TN, India
Healing of chronic lower extremity wounds is a global problem, especially in developing countries where traditional medicine is often used by the people in remote places. India has a rich tradition of plant based knowledge pertinent to healthcare. A survey of ethnomedicinal plant species used by Malayali’s to heal cut/ wounds in Vattal Hills of Dharmapuri was made. A large number of plants/ extracts/ decoctions/ pastes are used by tribals to heal wounds, cuts and burns. In the present study, an attempt has been made to document ethnobotanical knowledge base and methods employed by Malayali’s for treatment of cut/ wounds. A large number of ethnomedicinal plants used by the Malayali’s have not been validated for wound healing potential. The present investigation resulted in the identification of 82 medicinal plant species distributed across 39 families that are used by Malayali’s to heal cut/ wounds. This study is an attempt to gather the information on the existing ethnobotanical knowledge base and document the traditional claims toward the development of safe of effective herbal drugs for cut/ wounds. Results of the study is organized in table form depicting the botanical name, family, vernacular name and habit with a brief note on plant parts used and method of administration
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